Formation and properties of MnAs magnetic nanoscaled dots on sulfur-passivated semiconductor substrates

• Published in: Journal of crystal growth Vol. 301; pp. 619 - 622
• Main Authors: Kubo, K., Kanai, K., Okabayashi, J., Oshima, M., Ofuchi, H.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 01.04.2007; Elsevier
• Subjects: A1. Crystal structure; A1. Surface structure; A3. Molecular beam epitaxy; B1. Nanomaterials; B2. Magnetic materials; B2. Semiconducting III–V materials; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Growth from vapor; Materials science; Methods of crystal growth; physics of crystal growth; Methods of deposition of films and coatings; film growth and epitaxy; Molecular, atomic, ion, and chemical beam epitaxy; Other semiconductors; Physics; Specific materials; Structure and morphology; thickness; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Thin film structure and morphology; B1. Nanomaterials; A3. Molecular beam epitaxy; B2. Semiconducting III–V materials; A1. Crystal structure; A1. Surface structure; B2. Magnetic materials; Atomic force microscopy; Gallium arsenides; Crystal growth from vapors; X-ray absorption; Quantum interference devices; EXAFS; B2. Semiconducting III-V materials; Surface structure; Fine structure; Bl. Nanomaterials; SQUID devices; Mismatch lattice; Molecular beam epitaxy; Magnetic materials; Nanodot; Sulfur; Magnetic properties; Crystal structure; Al. Crystal structure; Al. Surface structure; III-V compound; Indium phosphides; Lattice energy; Crystal faces; Nanostructured materials; Surface energy; III-V semiconductors
• ISSN: 0022-0248; 1873-5002
• DOI: 10.1016/j.jcrysgro.2006.11.047

We have fabricated MnAs ferromagnetic nanoscaled dots on sulfur-passivated semiconductor substrates such as GaAs(0 0 1), GaAs(1 1 1)B, and InP(0 0 1) by low temperature molecular beam epitaxy (MBE). Atomic force microscopy (AFM) results reveal that the shape of MnAs dots depends on the surface energy of sulfur-passivated substrates. Extended X-ray absorption fine structure (EXAFS) and superconducting quantum interference device (SQUID) results suggest that MnAs dots on sulfur-passivated GaAs(0 0 1) are zb-type, while MnAs dots on sulfur-passivated GaAs(1 1 1)B and InP(0 0 1) are NiAs-type. We have found that the balance between substrate surface energy and lattice mismatch is essential to successfully fabricate zb-MnAs.